I have the following scenario:

1. Authenticated users can view a list of confidential documents (filenames in plaintext). Download is not allowed.
2. Authenticated users can click "Request" button and write a reason to submit a document request. The request will be sent to manager for approval (either by email or in Drupal).
3. Manager review the request and approval/reject the request. User can only download after request is approved.

It seems that module download_access is close to what I need. But it seems that no development has been going on. So I plan to write a module to cater this.

But I wonder is it possible to turn on and off a download link using condition checking modules (e.g. rules, actions and trigger, etc)? Any one has tried this before?